The invention relates to a method for the manufacture of electronic cards, as well as to cards obtained thereby.
The word "card" must be considered, in the present invention, in the broad sense, including especially any portable object with standardized dimensions, and comprising, firstly, a micromodule and, secondly, a body used as a portable carrier. However, the invention is aimed in particular at chip cards and, among these cards, at those cards that have contactless operations, wherein the micromodule is connected to an antenna for the electromagnetic transmission of data elements. Hereinafter in the description, the term "contactless card" will be understood to mean a card having exclusively contactless operation or else a hybrid card having contactless operation and standard contact-based operation.
The manufacture of electronic cards in large batches may be done according to different methods.
Certain methods make use of an injection, at a temperature of over 90.degree. C. and at high pressure of about 700 kg/cm2 for example, of a polymerized viscous thermoplastic material in the molten state into an enclosed cavity of a mold. After cooling below its melting point, this material forms a thickness of the body of the card.
However, such methods do not provide the possibility of a simple adjustment of the viscosity of the plastic material injected. Now, during the designing of a method for the manufacture of cards by injection, it is necessary to perform many tests, in particular by varying the viscosity of the material injected so as to arrive ultimately at an industrially acceptable optimum method with zero defects.